Ferroelectric FET Barrier Layer for Stable Memory Window

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Solution Overview

Problem

Existing ferroelectric field effect transistors face challenges in maintaining stable polarization switching and memory window performance due to direct contact between the channel layer and oxygen-deficient layer, leading to channel deterioration and reduced leakage current characteristics.

Innovation Solution

Incorporation of an oxide semiconductor channel with an oxygen-deficient layer having a higher concentration of oxygen vacancies and a diffusion barrier layer to prevent oxygen exchange, combined with a gate intermediate layer with graded nitrogen and oxygen concentrations, enhances polarization switching and memory window performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the channel layer is in direct contact with the oxygen-deficient layer, then the polarization switching capability is enhanced, but the channel layer deteriorates and leakage current increases

Engineering Contradiction:

Improvepolarization switching capabilityVSAvoidchannel layer deterioration

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

A diffusion barrier layer is introduced as an intermediary between the channel layer and the oxygen-deficient layer. This barrier layer prevents direct contact while still allowing the beneficial polarization switching effect to occur, thereby eliminating channel deterioration without sacrificing polarization switching capability.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The interface between the channel layer and oxygen-deficient layer is segmented by introducing the diffusion barrier layer. This segmentation separates the functions of channel conduction and polarization switching, allowing each to optimize independently while preventing harmful interactions.

Inventive Principle:

Principle #1Segmentation

2Reliability

If the diffusion barrier layer is made thicker to better prevent oxygen exchange, then channel protection is improved, but device complexity and manufacturing difficulty increase

Engineering Contradiction:

Improvechannel protectionVSAvoidstructure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The thickness of the diffusion barrier layer is optimized to a specific range (0.5-3 nm) that provides sufficient oxygen barrier functionality while minimizing additional complexity. This parameter optimization achieves effective channel protection without excessive structural complexity.

Inventive Principle:

Principle #35Parameter changes

3Reliability

If the oxygen-deficient layer is made thicker to increase polarization effect, then memory window is improved, but oxygen exchange with channel layer increases causing deterioration

Engineering Contradiction:

Improvememory windowVSAvoidoxygen exchange

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The diffusion barrier layer serves as a mediator that allows the oxygen-deficient layer to be sufficiently thick for memory window optimization while preventing oxygen from reaching and deteriorating the channel layer. The barrier layer decouples the thickness benefit from the harmful oxygen exchange.

Inventive Principle:

Principle #24Intermediary (Mediator)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The solution improves polarization switching capabilities and increases the memory window by allowing bidirectional polarization in the ferroelectric layer while preventing channel layer deterioration, resulting in low leakage current and high operational speed.

Implementation Method 1

a diffusion barrier layer between the channel layer and the oxygen-deficient layer and configured to reduce or prevent oxygen exchange between the channel layer and the oxygen-deficient layer

Methodology Applied

Scientific EffectDiffusion barrier: Diffusion Barrier

Implementation Method 2

Ferroelectrics are materials that have ferroelectricity, wherein spontaneous polarization is achieved by aligning internal electric dipole moments of the material such that, even when no electric field is applied from an external electric field source, the internal electric dipole moments remain aligned

Methodology Applied

Scientific EffectFerroelectricity: Polarisation

Data Source

PatentUS20260032916A1Ferroelectric field effect transistor, memory device, and neural network device

Publication Date: 2026.01.29 SAMSUNG ELECTRONICS CO LTD

AI summary

A ferroelectric field effect transistor includes a channel layer, a gate electrode facing the channel layer, a ferroelectric layer provided between the channel layer and the gate electrode, an oxygen-deficient layer provided between the channel layer and the ferroelectric layer, a diffusion barrier layer provided between the channel layer and the oxygen-deficient layer and configured to reduce or prevent oxygen exchange between the channel layer and the oxygen-deficient layer, and a source electrode and a drain electrode, electrically connected to the channel layer, wherein the channel layer and the oxygen-deficient layer include an oxide semiconductor material, and a concentration of oxygen vacancies in the oxygen-deficient layer may be greater than a concentration of oxygen vacancies in the channel layer.